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Delivering Advanced Engineering Solutions |
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Here at AESC, our staff has successfully utilized probabilistic risk assessment (PRA) methodology as an underlying tool for providing case by case risk assessment and management solutions to our clients. We have used off the shelf PRA software tools, as well as in house custom designed toolsets to meet our clients' requirements.
We have also developed a top-down, and bottom-up processes for performing risk assessments. The top-down process is used when dealing with an identified hazard or risk, that its contributors are unknown. This process which is also part of fault tree methodology, breaks down the contributors to lowest elements possible, in order to identify the most likely contributors. The bottom-up process is used in cases where potential risks haven’t been identified. In this process the system or process under study is modeled using FMECA and fault tree to explore and identify potential risks.
When potential risks have been identified, we use event tree analysis to model hazard progression sequences. Event tree models also allow us to quantify frequency and probability of each sequence, and relevant consequence. As part of our PRAM approach, we utilize FMECA, fault tree, and event tree analysis in order to produce a comprehensive probabilistic risk assessment. FMECA is typically used to flush out potential risks ranked by criticality. Combination of fault tree and event tree is also referred to as a cause-consequence diagram, where event trees are used to show consequences, and fault trees are used to show causes.
Our risk assessment process also includes safety integrity level (SIL) determination, in accordance with IEC 61508, and ISA S84. This enables our clients' products to comply with SIL classification for their respective industries. Determination of SIL is based on a probabilistic risk graph that is constructed using four parameters, "Consequence - C", "Exposure - F", "Probability of avoiding hazard - P", and "Likelihood of Event - W". Please see Safety Inegrity Level Analysis page for more details.
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